1. Field of the Invention
The present invention relates to a method and an apparatus for grinding axial workpieces, and in particular, to a method and an apparatus for grinding an axial workpiece having an oil seal fit portion on its outer circumferential surface to remove a turning lead portion thereof by dry process within a lathe.
2. Description of the Related Art
A number of constant velocity joints and other various types of automobile components include those axial parts that have an oil seal fit portion on their outer circumferential surface. Such axial parts are typically formed by grinding, but when formed by turning using a lathe, they may have somewhat coarse turning lead portions remaining at their oil seal fit portion. Such a remaining coarse turning lead portion may likely cause leakage of oil along the turning lead portion. Accordingly, the oil seal fit portion is generally finished by grinding to remove the turning lead portion.
However, in general, grinding fluid such as mineral oil is indispensable for grinding in order to prevent burning due to grinding. Use of grinding fluid causes deterioration of work environment due to scattering of the fluid or an increase in costs for treatment of used fluids. In these days, to solve such problems with grinding fluids, there is an increasing tendency to process some workpieces by dry cutting without any grinding fluid instead of grinding with grinding fluid. However, in an outer-diameter finish step for axial parts having an oil seal fit portion on their outer circumferential surface, it is difficult to generally employ dry processing by entirely changing grinding to cutting because there will still be a possibility that a coarse turning lead portion inevitably remains.